Ordinary waterbeds of the type or class here concerned with comprise upwardly opening rectangular frame structures including flat horizontal mattress supporting platforms and flat, vertically upwardly projecting side and end boards with straight horizontal top edges about their perimeters; and water or flotation mattresses arranged within the frame structures in supported engagement atop the platforms and in retained engagement with the side and end boards.
Waterbed frame structures are commonly fabricated of wood and the like and often lined or padded with various soft materials such as styrofoam. In more recent times, such frame structures have been formed entirely of molded styrofoam sections.
Ordinary waterbed flotation mattresses are generally simple bladder like units of flexible plastic sheeting such as polyvinylchloride, and are filled with any desired and suitable fluid medium, such as water. Fluid medium or water filled flotation mattresses are constructed or formed to substantially conform with the interior space defined by the bed frame structures with which they are to be related and have or define normally flat horizontal body supporting top walls, flat horizontal bottom walls and normally vertically side and end walls. The bottom, side and end walls normally establish flat supported engagement with the platforms and with the side and end boards of their related bed frame structures. The body supporting top walls of such mattresses normally occur on a horizontal plane substantially coincidental with the planes of the frame structures on which the upper edges of the side end boards occur.
In practice, the vertical extent or depth of flotation mattresses, that is, the normal vertical space or distance between the top and bottom walls and the depth of the water or fluid medium therein is, for example, about 8" and is such that when parts and/or portions of the bodies of persons (of maximum anticipated weight) are engaged on and supported by the top walls of the mattresses, the top walls are urged or depressed downwardly thereby, displacing volumes of water within the mattress to such an extent that the bodies are buoyantly supported. The depth or vertical extent of the mattresses is such that the top walls will not, under normal circumstances engage and come to rest on or "bottom out" on the bottom walls of the mattresses and against the platforms of the bed frames, when subjected to normal use.
Flotation mattresses of the character referred to above are fabricated of panels and/or pieces of plastic sheet stock cut, folded and welded together in accordance with predetermined patterns and procedures. The patterns, procedures and fabricating techniques employed by different manufacturers of such mattresses varies widely, but in most instances, the resulting mattresses are essentially alike as regards their basic configuration and definable top, bottom, side and end walls, noted in the preceding.
A major objection or shortcoming found in waterbeds resides in the tendency of the fluid medium or water within the mattresses to surge and create continuing diminishing motion, in the nature of waves, when bodies are initially engaged on the mattresses and when the bodies on the mattresses move or shift position. The noted surge and residual wave action is oftentimes quite disturbing to persons on the mattresses and is such that some persons experience motion sickness when surging and wave action is generated by the movment of their bodies or the bodies of others on the mattresses.
While the above noted surging and wave action generated in flotation mattresses is soothing and restful to some people, others cannot tolerate it. Accordingly, the attributes of waterbeds are the subject of some controversy which has caused adverse effects on the sale and use of such beds.
It has been determined that if the surging and wave action in waterbeds could be effectively eliminated or reduced to an extent that it was no longer a problem, many persons who cannnot or will not tolerate the surging and/or residual wave action experienced in the use of present day waterbeds, would find no objecton to and would purchase and adopt the use of such beds to gain the principal advantages afforded thereby; that is, the uniform, conforming and fluid body support such beds provide.
The prior art has long sought to eliminate or reduce the surging and wave action in flotation mattresses by the placement of baffles within the mattresses to slow or dampen the movement of water therein. Such efforts have met with limited or questionable success and have often been so costly to put into practice that they are economically impractical.
Other attempts or means by the prior art to eliminate and/or reduce the surge and wave action in waterbeds has been directed to the establishment of mattress structures which are combinations of and constitute a compromise between flotation mattresses and conventional resilient foam plastic mattresses. In such structures, resilient foam plastic mattress pads are arranged within the bottom portions of common flotation mattresses or are arranged beneath special flotation mattresses of limited or less than normal vertical extent whereby the depth and resulting volume of water or fluid medium, above the foam mattresses, is reduced to an extent that surging and residual wave action is notably reduced.
This reduction in surging and residual wave action is due to the reduction in the volume of free to flow and move water to a volume which will not support large or heavy surging and will not sustain notable residual wave action.
Some combination mattress structures of the character referred to above effectively reduce surging and wave action to acceptable levels but in doing so, reduce the depth and volume of water or fluid medium so that full buoyant support of the bodies of persons engaged on the mattresses is not assured and is oftentimes unattainable. Such combination of mattress structures are generally considered a compromise between true flotation mattresses and foam plastic mattresses and are condsidered to be of questionable value or effectiveness.